<!--
所有HTML元素都可以看作盒子，在CSS中box model用来在设计和布局时使用
用来封装html元素外边距margin、边框border、
内边距padding、实际内容content
-->

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width:100px;
            height:100px;
            background-color: red;
            padding: 50px 10px;
            border:5px solid blue;
            margin: 50px;
        }
    </style>

</head>
    <div>
        <p>This is a paragraph.</p>
        <p>This is another paragraph.</p>
    </div>
    <p>This is a paragraph outside the div.</p>
</body>
</html>